A Big Bet on Ameritrade

Call options for discount broker Ameritrade surge on no news as a major buyer bets on a rally.

TD Ameritrade wins the prize for the week's most unusual options trading pattern.

With Ameritrade (ticker: AMTD) down slightly at $19, someone bought 40,000 August $23 calls that will increase in value if the stock gains more than 20% by summer's end. That's a $1 million bet—not something you see every day in the options market.